Clasification Society Rulefinder 2020 - Version 9.33 - Fix
Common Structural Rules - Common Structural Rules for Bulk Carriers and Oil Tankers, January 2019 - Part 1 General Hull Requirements - Chapter 2 General Arrangement Design - Section 3 Compartment Arragement - 1 Cofferdams

1 Cofferdams

1.1 Definition

1.1.1 A cofferdam means an empty space arranged so that compartments on each side have no common boundary; a cofferdam may be located vertically or horizontally. As a rule, a cofferdam is to be kept gas-tight and is to be properly ventilated, provided with drainage arrangement, and of sufficient size to allow proper inspection, maintenance and safe evacuation.

1.2 Arrangement of cofferdams

1.2.1 Cofferdams are to be provided between compartments intended for liquid hydrocarbons (including fuel oil, lubricating oil) and those intended for fresh water (water for propelling machinery and boilers) as well as tanks intended for the carriage of liquid foam for fire extinguishing.

1.2.2 Furthermore, tanks carrying fresh water for human consumption are to be separated from other tanks containing substances hazardous to human health by cofferdams or other means as approved by the Society.

Note 1: Normally, tanks for fresh water and water ballast are considered non-hazardous.

1.2.3 Where a corner to corner situation occurs, tanks are not considered to be adjacent.

1.2.4 The cofferdams specified in [1.2.1] may be waived when deemed impracticable or unreasonable by the Society in relation to the characteristics and dimensions of the spaces containing such tanks, provided that:

  • the thickness of common boundary plates of adjacent tanks is increased, with respect to the thickness obtained according to Ch 6, Sec 4, by 2 mm in the case of tanks carrying fresh water or boiler feed water, and by 1 mm in all other cases,
  • the sum of the throats of the weld fillets at the edges of these plates is not less than the thickness of the plates themselves,
  • the structural test is carried out with a test pressure increased by 1 m with respect to Ch 1, Sec 2, [3.8.4].
Parent topic: Section 3 Compartment Arragement
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